Merge DashLiveMpdFetcher logic into generic ManifestFetcher.

This allows ManifestFetcher to both execute the initial
manifest load and be plugged into an ExoPlayer ChunkSource,
where it can be used for repeated manfiest refreshes during
live playback.

demo/src/main/java/com/google/android/exoplayer/demo/full/player/DashVodRendererBuilder.java

@@ -52,11 +52,11 @@ import com.google.android.exoplayer.util.Util;
 import android.annotation.TargetApi;
 import android.media.MediaCodec;
 import android.media.UnsupportedSchemeException;
-import android.os.AsyncTask;
 import android.os.Handler;
 import android.util.Pair;
 import android.widget.TextView;
 
+import java.io.IOException;
 import java.util.ArrayList;
 
 /**
@@ -96,13 +96,13 @@ public class DashVodRendererBuilder implements RendererBuilder,
     this.player = player;
     this.callback = callback;
     MediaPresentationDescriptionParser parser = new MediaPresentationDescriptionParser();
-    ManifestFetcher<MediaPresentationDescription> mpdFetcher =
-        new ManifestFetcher<MediaPresentationDescription>(parser, this);
-    mpdFetcher.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, url, contentId);
+    ManifestFetcher<MediaPresentationDescription> manifestFetcher =
+        new ManifestFetcher<MediaPresentationDescription>(parser, contentId, url);
+    manifestFetcher.singleLoad(player.getMainHandler().getLooper(), this);
   }
 
   @Override
-  public void onManifestError(String contentId, Exception e) {
+  public void onManifestError(String contentId, IOException e) {
     callback.onRenderersError(e);
   }
 

demo/src/main/java/com/google/android/exoplayer/demo/full/player/SmoothStreamingRendererBuilder.java

@@ -43,7 +43,6 @@ import com.google.android.exoplayer.upstream.DataSource;
 import com.google.android.exoplayer.upstream.DefaultBandwidthMeter;
 import com.google.android.exoplayer.upstream.HttpDataSource;
 import com.google.android.exoplayer.util.ManifestFetcher;
-import com.google.android.exoplayer.util.ManifestFetcher.ManifestCallback;
 import com.google.android.exoplayer.util.Util;
 
 import android.annotation.TargetApi;
@@ -52,6 +51,7 @@ import android.media.UnsupportedSchemeException;
 import android.os.Handler;
 import android.widget.TextView;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.UUID;
 
@@ -59,7 +59,7 @@ import java.util.UUID;
  * A {@link RendererBuilder} for SmoothStreaming.
  */
 public class SmoothStreamingRendererBuilder implements RendererBuilder,
-    ManifestCallback<SmoothStreamingManifest> {
+    ManifestFetcher.ManifestCallback<SmoothStreamingManifest> {
 
   private static final int BUFFER_SEGMENT_SIZE = 64 * 1024;
   private static final int VIDEO_BUFFER_SEGMENTS = 200;
@@ -88,16 +88,15 @@ public class SmoothStreamingRendererBuilder implements RendererBuilder,
   public void buildRenderers(DemoPlayer player, RendererBuilderCallback callback) {
     this.player = player;
     this.callback = callback;
-
     SmoothStreamingManifestParser parser = new SmoothStreamingManifestParser();
     ManifestFetcher<SmoothStreamingManifest> manifestFetcher =
-        new ManifestFetcher<SmoothStreamingManifest>(parser, this);
-    manifestFetcher.execute(url + "/Manifest", contentId);
+        new ManifestFetcher<SmoothStreamingManifest>(parser, contentId, url + "/Manifest");
+    manifestFetcher.singleLoad(player.getMainHandler().getLooper(), this);
   }
 
   @Override
-  public void onManifestError(String contentId, Exception e) {
-    callback.onRenderersError(e);
+  public void onManifestError(String contentId, IOException exception) {
+    callback.onRenderersError(exception);
   }
 
   @Override

demo/src/main/java/com/google/android/exoplayer/demo/simple/DashVodRendererBuilder.java

@@ -42,9 +42,9 @@ import com.google.android.exoplayer.util.ManifestFetcher;
 import com.google.android.exoplayer.util.ManifestFetcher.ManifestCallback;
 
 import android.media.MediaCodec;
-import android.os.AsyncTask;
 import android.os.Handler;
 
+import java.io.IOException;
 import java.util.ArrayList;
 
 /**
@@ -76,13 +76,13 @@ import java.util.ArrayList;
   public void buildRenderers(RendererBuilderCallback callback) {
     this.callback = callback;
     MediaPresentationDescriptionParser parser = new MediaPresentationDescriptionParser();
-    ManifestFetcher<MediaPresentationDescription> mpdFetcher =
-        new ManifestFetcher<MediaPresentationDescription>(parser, this);
-    mpdFetcher.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, url, contentId);
+    ManifestFetcher<MediaPresentationDescription> manifestFetcher =
+        new ManifestFetcher<MediaPresentationDescription>(parser, contentId, url);
+    manifestFetcher.singleLoad(playerActivity.getMainLooper(), this);
   }
 
   @Override
-  public void onManifestError(String contentId, Exception e) {
+  public void onManifestError(String contentId, IOException e) {
     callback.onRenderersError(e);
   }
 

demo/src/main/java/com/google/android/exoplayer/demo/simple/SmoothStreamingRendererBuilder.java

@@ -42,6 +42,7 @@ import com.google.android.exoplayer.util.ManifestFetcher.ManifestCallback;
 import android.media.MediaCodec;
 import android.os.Handler;
 
+import java.io.IOException;
 import java.util.ArrayList;
 
 /**
@@ -74,12 +75,12 @@ import java.util.ArrayList;
     this.callback = callback;
     SmoothStreamingManifestParser parser = new SmoothStreamingManifestParser();
     ManifestFetcher<SmoothStreamingManifest> manifestFetcher =
-        new ManifestFetcher<SmoothStreamingManifest>(parser, this);
-    manifestFetcher.execute(url + "/Manifest", contentId);
+        new ManifestFetcher<SmoothStreamingManifest>(parser, contentId, url + "/Manifest");
+    manifestFetcher.singleLoad(playerActivity.getMainLooper(), this);
   }
 
   @Override
-  public void onManifestError(String contentId, Exception e) {
+  public void onManifestError(String contentId, IOException e) {
     callback.onRenderersError(e);
   }
 

library/src/main/java/com/google/android/exoplayer/util/ManifestFetcher.java

@@ -15,114 +15,297 @@
  */
 package com.google.android.exoplayer.util;
 
-import android.net.Uri;
-import android.os.AsyncTask;
+import com.google.android.exoplayer.upstream.Loader;
+import com.google.android.exoplayer.upstream.Loader.Loadable;
+
+import android.os.Looper;
+import android.os.SystemClock;
+import android.util.Pair;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;
+import java.util.concurrent.CancellationException;
 
 /**
- * An {@link AsyncTask} for loading and parsing media manifests.
+ * Performs both single and repeated loads of media manfifests.
  *
- * @param <T> The type of the manifest being parsed.
+ * @param <T> The type of manifest.
  */
-public class ManifestFetcher<T> extends AsyncTask<String, Void, T> {
+public class ManifestFetcher<T> implements Loader.Callback {
 
   /**
-   * Invoked with the result of a manifest fetch.
+   * Callback for the result of a single load.
    *
-   * @param <T> The type of the manifest being parsed.
+   * @param <T> The type of manifest.
    */
   public interface ManifestCallback<T> {
 
     /**
-     * Invoked from {@link #onPostExecute(Object)} with the parsed manifest.
+     * Invoked when the load has successfully completed.
      *
      * @param contentId The content id of the media.
-     * @param manifest The parsed manifest.
+     * @param manifest The loaded manifest.
      */
     void onManifest(String contentId, T manifest);
 
     /**
-     * Invoked from {@link #onPostExecute(Object)} if an error occurred.
+     * Invoked when the load has failed.
      *
      * @param contentId The content id of the media.
-     * @param e The error.
+     * @param e The cause of the failure.
      */
-    void onManifestError(String contentId, Exception e);
+    void onManifestError(String contentId, IOException e);
 
   }
 
-  public static final int DEFAULT_HTTP_TIMEOUT_MILLIS = 8000;
+  /* package */ final ManifestParser<T> parser;
+  /* package */ final String manifestUrl;
+  /* package */ final String contentId;
 
-  private final ManifestParser<T> parser;
-  private final ManifestCallback<T> callback;
-  private final int timeoutMillis;
+  private int enabledCount;
+  private Loader loader;
+  private ManifestLoadable currentLoadable;
 
-  private volatile String contentId;
-  private volatile Exception exception;
+  private int loadExceptionCount;
+  private long loadExceptionTimestamp;
+  private IOException loadException;
+
+  private volatile T manifest;
+  private volatile long manifestLoadTimestamp;
 
   /**
-   * @param callback The callback to provide with the parsed manifest (or error).
+   * @param parser A parser to parse the loaded manifest data.
+   * @param contentId The content id of the content being loaded. May be null.
+   * @param manifestUrl The manifest location.
    */
-  public ManifestFetcher(ManifestParser<T> parser, ManifestCallback<T> callback) {
-    this(parser, callback, DEFAULT_HTTP_TIMEOUT_MILLIS);
-  }
-
-  /**
-   * @param parser Parses the manifest from the loaded data.
-   * @param callback The callback to provide with the parsed manifest (or error).
-   * @param timeoutMillis The timeout in milliseconds for the connection used to load the data.
-   */
-  public ManifestFetcher(ManifestParser<T> parser, ManifestCallback<T> callback,
-      int timeoutMillis) {
+  public ManifestFetcher(ManifestParser<T> parser, String contentId, String manifestUrl) {
     this.parser = parser;
-    this.callback = callback;
-    this.timeoutMillis = timeoutMillis;
+    this.contentId = contentId;
+    this.manifestUrl = manifestUrl;
+  }
+
+  /**
+   * Performs a single manifest load.
+   *
+   * @param callbackLooper The looper associated with the thread on which the callback should be
+   *     invoked.
+   * @param callback The callback to receive the result.
+   */
+  public void singleLoad(Looper callbackLooper, final ManifestCallback<T> callback) {
+    SingleFetchHelper fetchHelper = new SingleFetchHelper(callbackLooper, callback);
+    fetchHelper.startLoading();
+  }
+
+  /**
+   * Gets a {@link Pair} containing the most recently loaded manifest together with the timestamp
+   * at which the load completed.
+   *
+   * @return The most recently loaded manifest and the timestamp at which the load completed, or
+   *     null if no manifest has loaded.
+   */
+  public T getManifest() {
+    return manifest;
+  }
+
+  /**
+   * Gets the value of {@link SystemClock#elapsedRealtime()} when the last load completed.
+   *
+   * @return The value of {@link SystemClock#elapsedRealtime()} when the last load completed.
+   */
+  public long getManifestLoadTimestamp() {
+    return manifestLoadTimestamp;
+  }
+
+  /**
+   * Gets the error that affected the most recent attempt to load the manifest, or null if the
+   * most recent attempt was successful.
+   *
+   * @return The error, or null if the most recent attempt was successful.
+   */
+  public IOException getError() {
+    if (loadExceptionCount <= 1) {
+      // Don't report an exception until at least 1 retry attempt has been made.
+      return null;
+    }
+    return loadException;
+  }
+
+  /**
+   * Enables refresh functionality.
+   */
+  public void enable() {
+    if (enabledCount++ == 0) {
+      loadExceptionCount = 0;
+      loadException = null;
+    }
+  }
+
+  /**
+   * Disables refresh functionality.
+   */
+  public void disable() {
+    if (--enabledCount == 0) {
+      if (loader != null) {
+        loader.release();
+        loader = null;
+      }
+    }
+  }
+
+  /**
+   * Should be invoked repeatedly by callers who require an updated manifest.
+   */
+  public void requestRefresh() {
+    if (loadException != null && SystemClock.elapsedRealtime()
+        < (loadExceptionTimestamp + getRetryDelayMillis(loadExceptionCount))) {
+      // The previous load failed, and it's too soon to try again.
+      return;
+    }
+    if (loader == null) {
+      loader = new Loader("manifestLoader");
+    }
+    if (!loader.isLoading()) {
+      currentLoadable = new ManifestLoadable();
+      loader.startLoading(currentLoadable, this);
+    }
   }
 
   @Override
-  protected final T doInBackground(String... data) {
-    try {
-      contentId = data.length > 1 ? data[1] : null;
-      String urlString = data[0];
+  public void onLoadCompleted(Loadable loadable) {
+    if (currentLoadable != loadable) {
+      // Stale event.
+      return;
+    }
+
+    manifest = currentLoadable.result;
+    manifestLoadTimestamp = SystemClock.elapsedRealtime();
+    loadExceptionCount = 0;
+    loadException = null;
+  }
+
+  @Override
+  public void onLoadCanceled(Loadable loadable) {
+    // Do nothing.
+  }
+
+  @Override
+  public void onLoadError(Loadable loadable, IOException exception) {
+    if (currentLoadable != loadable) {
+      // Stale event.
+      return;
+    }
+
+    loadExceptionCount++;
+    loadExceptionTimestamp = SystemClock.elapsedRealtime();
+    loadException = new IOException(exception);
+  }
+
+  private long getRetryDelayMillis(long errorCount) {
+    return Math.min((errorCount - 1) * 1000, 5000);
+  }
+
+  private class SingleFetchHelper implements Loader.Callback {
+
+    private final Looper callbackLooper;
+    private final ManifestCallback<T> wrappedCallback;
+    private final Loader singleUseLoader;
+    private final ManifestLoadable singleUseLoadable;
+
+    public SingleFetchHelper(Looper callbackLooper, ManifestCallback<T> wrappedCallback) {
+      this.callbackLooper = callbackLooper;
+      this.wrappedCallback = wrappedCallback;
+      singleUseLoader = new Loader("manifestLoader:single");
+      singleUseLoadable = new ManifestLoadable();
+    }
+
+    public void startLoading() {
+      singleUseLoader.startLoading(callbackLooper, singleUseLoadable, this);
+    }
+
+    @Override
+    public void onLoadCompleted(Loadable loadable) {
+      try {
+        manifest = singleUseLoadable.result;
+        manifestLoadTimestamp = SystemClock.elapsedRealtime();
+        wrappedCallback.onManifest(contentId, singleUseLoadable.result);
+      } finally {
+        releaseLoader();
+      }
+    }
+
+    @Override
+    public void onLoadCanceled(Loadable loadable) {
+      // This shouldn't ever happen, but handle it anyway.
+      try {
+        IOException exception = new IOException("Load cancelled", new CancellationException());
+        wrappedCallback.onManifestError(contentId, exception);
+      } finally {
+        releaseLoader();
+      }
+    }
+
+    @Override
+    public void onLoadError(Loadable loadable, IOException exception) {
+      try {
+        wrappedCallback.onManifestError(contentId, exception);
+      } finally {
+        releaseLoader();
+      }
+    }
+
+    private void releaseLoader() {
+      singleUseLoader.release();
+    }
+
+  }
+
+  private class ManifestLoadable implements Loadable {
+
+    private static final int TIMEOUT_MILLIS = 10000;
+
+    /* package */ volatile T result;
+    private volatile boolean isCanceled;
+
+    @Override
+    public void cancelLoad() {
+      // We don't actually cancel anything, but we need to record the cancellation so that
+      // isLoadCanceled can return the correct value.
+      isCanceled = true;
+    }
+
+    @Override
+    public boolean isLoadCanceled() {
+      return isCanceled;
+    }
+
+    @Override
+    public void load() throws IOException, InterruptedException {
       String inputEncoding = null;
       InputStream inputStream = null;
       try {
-        Uri baseUri = Util.parseBaseUri(urlString);
-        HttpURLConnection connection = configureHttpConnection(new URL(urlString));
+        HttpURLConnection connection = configureHttpConnection(new URL(manifestUrl));
         inputStream = connection.getInputStream();
         inputEncoding = connection.getContentEncoding();
-        return parser.parse(inputStream, inputEncoding, contentId, baseUri);
+        result = parser.parse(inputStream, inputEncoding, contentId,
+            Util.parseBaseUri(manifestUrl));
       } finally {
         if (inputStream != null) {
           inputStream.close();
         }
       }
-    } catch (Exception e) {
-      exception = e;
-      return null;
     }
-  }
 
-  @Override
-  protected final void onPostExecute(T manifest) {
-    if (exception != null) {
-      callback.onManifestError(contentId, exception);
-    } else {
-      callback.onManifest(contentId, manifest);
+    private HttpURLConnection configureHttpConnection(URL url) throws IOException {
+      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+      connection.setConnectTimeout(TIMEOUT_MILLIS);
+      connection.setReadTimeout(TIMEOUT_MILLIS);
+      connection.setDoOutput(false);
+      connection.connect();
+      return connection;
     }
-  }
 
-  private HttpURLConnection configureHttpConnection(URL url) throws IOException {
-    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
-    connection.setConnectTimeout(timeoutMillis);
-    connection.setReadTimeout(timeoutMillis);
-    connection.setDoOutput(false);
-    connection.connect();
-    return connection;
   }
 
 }